I am trying to add two strings to a hash map. the first being the key, a 3 digit code that can have duplicates, and the value to store in an ArrayList. From what I've read, when add a key to the hashmap that is a duplicate, the previous gets overwritten and that is why I am trying to put the values in an array list. I was hoping that when the key is looked up, it would print all the values associated with that key:
class library{
HashMap<String, ArrayList<String>> checkoutBooks =
new HashMap<String, ArrayList<String>>() ;
ArrayList<String> patName = new ArrayList<String>() ;
public void checkoutBook(String isbn, String patron) {
patName.add(patron) ;
I am trying to create a class (DVD) with an instance variable that references a map, the constructor for this class must create an empty map and assign it to the instance variable map. I want to populate this map with instances of a different class called tv series, I am using blueJ, I am not sure why this doesn't work
Java Code:
import java.util.*; public class DVD { public static Map<String, TvSeries>DVD; public TvSeries program;
I want to generate a Hash key for a [ Nested Hierarchical nodes]. Any lightweight non-cryptographic hash map functions which generate a key, so that I can use this hashkey to comparison purposes.
NOTE: Security is not a concern for me, I just want to create a Unique ID.
In linkedHashSet are the elements stored according to the insertion order or according to the hash value. If the elements are stored according to the insertion order then why is it not named as LinkedSet instead of LinkedHashSet? Why is the word hash used in LinkedHashSet?
I am implementing the hash join algorithm for a project with a hard coded hash function. I've hashed the first relation and I've hashed the second relation. The problem is when hashing the second relation I only know how to add the tuple from the second relation into a third relation and not also access the first relation tuple at that time
The "hashtable" structure contains the hashcode of my key as well as the tuple stored in a string. This code below is taking place in the hashing of the second table, my function determines that both these tuples share the same hash code based on the first element in the tuple (element 0) so I add the tuple from my second relation to the qRelation but I also want to add the tuple from the hashtable at that point and I don't know how to access that string
if(hashtable.containsKey(tuple/*(RELATIONA)*/.get(0).hashCode())) { //Add the tuple from relation A into qRelation wich matches the //above condition qRelation.addAll(tuple/*(RELATIONB)*/); }
I am having an array of strings and i want to find out whether these strings contained in the array contain a similar character or not.For example i am having following strings in the array of string:
aadafbd dsfgdfbvc sdfgyub fhjgbjhjd
my program should provide following result: 3 because i have 3 characters which are similar in all the strings of the array(f,b,d).
I have to write a resize method so that when my Bucket gets to a certain point, then it resizes the bucket when it is called. What is happening is, I am getting strange results when I run the method. My mean bucket length should be at 2.5 for the last insertion, but I am getting something like 0.1346. Here is my dictionary class
// The "Dictionary" class. // The Dictionary class implemented using hashing. Hash buckets are used. A dictionary contains a set of data elements with corresponding keys. Each element is inserted into the dictionary with a key. Later the key can be used to look up the element. Using the key, an element can be changed or it can be deleted from the dictionary. There is also an operation for checking to see if the dictionary is empty.
package dictionary; public class Dictionary { protected final static int MAX_BUCKETS = 1000; // number of buckets protected DictHashEntry[] buckets; // the bucket array private int collisionCount = 0;
I have a drop-down which contains the four sections simple buttons(filters). When click any of these buttons some settings are applied. I have successfully auotmated it using simple if else and switch but in that case i have to use 8 parameters(8 are the number of button)
public void editFilters(WebElement filter1, WebElement filter2, WebElement filter3, WebElement filter4,WebElement filter5,WebElement filter6,WebElement filter7,WebElement filter8 String edit, String expectedColour) { switch (edit) { case "selectFilter": if (filter1 != null) {
[Code] .....
But want to make it more effective by using hashes. I do not want to use 8 different parameters to perform action on the respective button.
So now what i want to implement.
Create a method in which i pass the parameter1 as hash and 2nd parameter as 0 or 1, 0 means unSelectFilter and 1 means select the filter.
With parameter 1, in code i want to pass the name or xpath or anything else for any number of filters , that those filters names should be stored into that hash and then by passing 0 or 1, i can select/unselect those filters.
I can sort strings in a collection by uppercase and then lowercase though I was wondering if there is any way of doing it in reverse, sorting by lowercase then by uppercase.
So I am supposed to be changing infix notation to postfix notation using stacks. This is simply taking a string "3 + 5 * 6" (infix) and turning it into (3 5 6 * +" (postfix).
To do this, we are to scan the string from left to right and when we encounter a number, we just add it to the final string, but when we encounter an operand, we throw it on the stack. Then if the next operand has a higher input precedence than the stack precedence of the operator on the top of the stack, we add that operator to the stack too, otherwise we pop from the stack THEN add the new operator.
I am supposed to be utilizing a hash map but I don't see how you would go about doing this. We are supposed to store operators on the hash map but operators need their own character, input precedence, stack precedence, and rank. How do you use a hash map when you need to tie a character to 3 values instead of just 1? I just don't get it.
The following is our Operator class that we are to use. Another problem is this isn't really supposed to be modified, yet we were given two important variables (inputPrecedence and outputPrecedence) that we can't have nothing to be initialized to and no way of accessing? So that might be where a hash map comes in but I am not sure. I am not very sure on how they exactly work anyway...
public class Operator implements Comparable<Operator> { public char operator; // operator privateint inputPrecedence; // input precedence of operator in the range [0, 5] privateint stackPrecedence; // stack precedence of operator in the range [-1, 3]
[Code] ....
So my question mostly revolves around how I tie an Operator character to its required values, so I can use it in my code to test two operators precedence values.
My original thought was turn string into character array, but then I would need nested for/while loops to check if it is a number or letter, or if it is an operator and thus result in O(n^2) time
Its supposed to notify the user if they have a palindrome, but keeps returning true even when I type, "hello".
import java.util.Scanner; public class PalinDrome { public static void main(String[] args) { String line; Scanner input = new Scanner(System.in); System.out.print("Please enter a word ");
I need my code to print out the top three most common IP Addresses in the ArrayList. Right now I have it printing out the top IP Address. I am a little confused as to how to get it to print out three. Every time I change something, It doesn't give me the correct results
My Code: public class Log_File_Analysis { private static ArrayList<String> ipAddress = new ArrayList<>(); private static String temp , mostCommon; static int max = 0; static int num = 0;
public static void main(String[] args) throws Exception { String s = "oldString"; reverse(s); System.out.println(s); // oldString } public static void modifyString(String s) { s = "newString"; System.out.println(s); // newString }
I thought the first print statement would print "newString" as String is an object, and when we pass objects between methods, changing state of the object in any method reflects across the methods.
So the while loop I am trying to use is: while( type != "EXIT" ) { type = input.next(); }
The problem is that typing in EXIT doesn't end the loop like I want it to. I also tried input.nextLine(); but neither of them work. The loop is being used to fill an ArrayList so the number of elements can change based on how many they want. What am I doing wrong, or what alternatives do I have?
covers switch statements and if/else statements. Java doesn't like the Strings for some reason. My instructor does her strings just like this and it works for her. I can figure out the rest of the program if I can only get around the: "java error35: sSymbol variable might not have been initialized.
import java.util.*; public class RockPaperScissors { public static void main(String[] args) { //generate outcome int symbol = (int)(Math.random() * 4); String sSymbol;
I am making a simple calculator. I want the user to input either string "add" or "subtract" and then it will take two numbers and either add or subtract them. I cannot get the if statement to work with a string!
import java.util.Scanner; public class newcalc { public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("Enter add or subtract");
Im trying to make a question game, much like a spin off from Trivial Pursuit. In this code, I call classes to get a random number. This number determines what category the question will be from. Coinciding with this number, the "if" statements go and pull the questions and answers from an alternate class. My problem is that when I try and output what should be the question and the 3 answers, its outputs "null" for each String?
This is my first class, which is just the class for the player.
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